The new roughly $200 million proposal, however, would take significantly longer to complete — stretching construction for as long as seven years in order to maximize state aid and drive down the share of the cost paid by city taxpayers, the district's consultant said Thursday.

Representatives of the consultant, CSArch, sketched the proposal in broad strokes for the school board Thursday -— about a month after school officials reacted with what they described as "sticker shock" to three earlier plans.

The plans ranged from a $221 million renovation of the existing building on Washington Avenue to the $242.4 million construction of an entirely new building on the same site. In between sat a $230.7 million combination of new construction and renovation.

Superintendent Marguerite Vanden Wyngaard said officials recognized those figures were "not in line with what the community could afford."

Instead, the consultants have begun drafting a plan that would still incorporate many of the same goals — like reducing the density of classrooms by increasing square-footage per student and ensuring more classrooms have access to natural light -— while also significantly cutting how much of the renovations must be paid for by local taxpayers.

By extending the building schedule from between three and four years to between five and seven, the district would be able to tap its limit for state construction aid twice because the cap recycles every five years, said Richard Peckham, an executive principal and vice president at CSArch.

"We can deliver the plan we showed you tonight for under $200 million," Peckham said, citing estimates drafted by Turner Construction.

The consultants could not immediately provide details on how the newest concept would impact property tax bills, but because the plan would benefit from more state aid, the local share of the project paid by taxpayers would drop, they said.

Peckham said the local share would drop by between $30 million and $70 million compared to the original three proposals.

The estimated annual tax impacts of the previous options on a $150,000 home ranged from $185 to $287, according to data given the board last month.

Simply doing nothing and replacing obsolete systems like heating, air conditioning, fire alarms and the roof on the existing building would cost between $20 million and $30 million, Peckham told board members.

The new plans for the school are an outgrowth of a 20-month community planning process and pressure from the state to radically remake the school -— educationally and physically -— in the wake of persistently low performance.

In late 2011, a plan appeared near to relocate the school and its roughly 2,200 students from midtown to the uptown Harriman State Office Campus — a move long favored by former Mayor Jerry Jennings — but never came to fruition.

The board has not yet committed to the renovation plan and is expecting more detail, including the tax impact, next month.

Even then, whatever plan the board chooses will have to be approved by voters. In June, Vanden Wyngaard said she was hopeful a referendum on the project could be on the ballot as soon as December.

While that's still a possibility, district spokeswoman Lisa Angerame said Thursday that the pursuit of the fourth option could make that timeline more challenging.

Board member Ginnie Farrell noted that while the extended construction schedule would help dampen the project's impact on a tax base that is "already very depressed," she said it would force the school officials to cope with several more years of disruption.

"The longer-term building project will take some more planning on our end," Farrell said.

The center sits next to the existing high school on the corner of Washington and North Main avenues. The district has wanted the land since 2012.

But the Army's discovery of perchloroethylene contamination in groundwater on the fence line that separates the reserve center and high school could block its transfer from federal jurisdiction for as long as two years, complicating its potential role in the high school's future.